package source;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;

import java.security.spec.AlgorithmParameterSpec;

public class AESEncrypter
{
        Cipher ecipher;
        Cipher dcipher;

        public AESEncrypter(SecretKey key)
        {
                // Create an 8-byte initialization vector
                byte[] iv = new byte[]
                {
                        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
                };

                AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
                try
                {
                        ecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
                        dcipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

                        // CBC requires an initialization vector
                        ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
                        dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
                }
                catch (Exception e)
                {
                        e.printStackTrace();
                }
        }

        // Buffer used to transport the bytes from one stream to another
        byte[] buf = new byte[1024];

        public void encrypt(InputStream in, OutputStream out)
        {
                try
                {
                        // Bytes written to out will be encrypted
                        out = new CipherOutputStream(out, ecipher);

                        // Read in the cleartext bytes and write to out to encrypt
                        int numRead = 0;
                        while ((numRead = in.read(buf)) >= 0)
                        {
                                out.write(buf, 0, numRead);
                        }
                        out.close();
                }
                catch (java.io.IOException e)
                {
                }
        }

        public void decrypt(InputStream in, OutputStream out)
        {
                try
                {
                        // Bytes read from in will be decrypted
                        in = new CipherInputStream(in, dcipher);

                        // Read in the decrypted bytes and write the cleartext to out
                        int numRead = 0;
                        while ((numRead = in.read(buf)) >= 0)
                        {
                                out.write(buf, 0, numRead);
                        }
                        out.close();
                }
                catch (java.io.IOException e)
                {
                }
        }

        public static void main(String args[])
        {
                try
                {
                        // Generate a temporary key. In practice, you would save this key.
                        // See also e464 Encrypting with DES Using a Pass Phrase.

                        KeyGenerator    kgen    =       KeyGenerator.getInstance("AES");
                        kgen.init(128);
                        SecretKey key                   =       kgen.generateKey();

                        // Create encrypter/decrypter class
                        AESEncrypter encrypter = new AESEncrypter(key);

                        // Encrypt
                        encrypter.encrypt(new FileInputStream("DESTest.txt"),new FileOutputStream("Encrypted.txt"));
                        // Decrypt
                        encrypter.decrypt(new FileInputStream("Encrypted.txt"),new FileOutputStream("Decrypted.txt"));
                }
                catch (Exception e)
                {
                        e.printStackTrace();
                }
        }
}
